Synthesis and physiological implications of melanic pigments (Review)

Mărănducă, Minela Aida; Brănişteanu, D; Şerban, Dragomir Nicolae; Brănișteanu, Dumitru; Stoleriu, Gabriela; Manolache, Nicuta; Șerban, Ionela Lăcrămioara

doi:10.3892/ol.2019.10071

Cited by 70 publications

(56 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The redetachment of the retina is also a factor that contributes additionally to the inflammatory cascade by releasing supplementary cytokines and pigment epithelium cells. When considering the percentage of reoperated patients due to redetachment, the values obtained in this retrospective study are comparable to literature data (18)(19)(20). However, some reinterventions were effectuated for reasons not related to the inflammatory process, such as IOL displacement or vitreous hemorrhage.…”

Section: Discussionsupporting

confidence: 83%

Outcomes of simultaneous vs. sequential pars plana vitrectomy and cataract surgery

Moraru

Costin

Moraru³

et al. 2020

Exp Ther Med

Self Cite

View full text Add to dashboard Cite

The coexistence of cataract and vitreoretinal diseases is common in clinical practice. The technological achievements of the last decade in both types of surgeries, allow simultaneous interventions on lens and retina. This retrospective study assessed the morphofunctional results obtained after performing simultaneous surgeries in a series of 87 patients presenting with both pathologies. The cases were retrospectively reviewed from their clinical records from 2017 to 2019. The patients were divided into two groups: group 1 comprising 41 cases underwent the combined procedure and group 2 comprising 46 patients underwent vitrectomy, followed by cataract surgery after 3-10 months. The functional and anatomical outcomes and the complications were assessed pre-and post-operatively. The statistical analysis was carried out by MaxStat software. The final best corrected visual acuity (BCVA), in group 1 was <0.1 in 4.88% of the cases, 0.1 to 0.3 in 17.07%, 0.3 to 0.5 in 51.22% and >0.5 in 26.83% eyes. In group 2, the final BCVA, after both surgeries were completed was <0.1 in 8.7% cases, 0.1 to 0.3 in 30.43%, 41.3% were 0.3 to 0.5 and 19.57% were >0.5. During the cataract surgery, the most common intraoperative complication was miosis, followed by posterior capsule rupture. Postoperative, 12.2% cases from group 1 developed an immediate inflammatory reaction in the anterior chamber, and 17.07% presented with posterior capsular opacification (PCO). Simultaneous surgery is safe and effective in obtaining a good morphological and functional result and offers the advantage of a clear eye media that allows a safer vitrectomy and thus a quicker rehabilitation of the patient. The analysis of the risks and benefits of each procedure should be taken into account and the cases selected individually for either simultaneous or sequential surgery in order to obtain the best outcomes.

show abstract

Section: Discussionsupporting

confidence: 83%

Outcomes of simultaneous vs. sequential pars plana vitrectomy and cataract surgery

Moraru

Costin

Moraru³

et al. 2020

Exp Ther Med

Self Cite

View full text Add to dashboard Cite

show abstract

“…Maintaining significant adhesion of neurosensory retina to the retinal pigment epithelium is the direct consequence of surface tension, SIO being immiscible with water. Increased viscosity provides more surface tension and also less emulsification rate as indicated by in vitro studies ( 1 , 4 , 5 ). In real life, these advantages might not be clinically significant if endotamponade lasts no more than 6 months ( 4 ).…”

Section: Introductionmentioning

confidence: 99%

Intraocular pressure changes during and after silicone oil endotamponade (Review)

et al. 2020

Self Cite

View full text Add to dashboard Cite

Silicone oil (SIO) has rapidly become an indispensable adjunct in vitreoretinal surgery. Constant improvements in purity and also in viscosity have not totally prevented specific complications that may occur during endotamponade. Results of in vitro studies that suggested that higher viscosity silicone oil might be superior in terms of stability and safety are confirmed in real life only if endotamponade lasts for more than 6 months. Intraocular pressure changes induced by the silicone oil endotamponade or oil extraction are documented from its very first use and are potentially threatening vision. The purpose of this review is to update current knowledge on the incidence, risk factors, pathogenesis, and management of secondary silicone oil glaucoma. Also, in a retrospective evaluation on cases with complex retinal detachments that underwent 23G vitrectomy and high viscosity SIO endotamponade, we have noticed that a considerable number of cases developed significant intraocular pressure changes during SIO endotamponade and after SIO removal, especially in early postoperative period.

show abstract

“…4 The biosynthesis and enzymology of MNs in melanocytes have been extensively studied and reviewed. 6,7 In this context the enzyme tyrosinase has received a lot of attention. [8][9][10] Tyrosinase is responsible for the first steps of the MN biosynthesis: the hydroxylation of L-tyrosine to L-DOPA and subsequent oxidation to L-dopaquinone.…”

Section: Introductionmentioning

confidence: 99%

Melanogenesis: A Search for Pheomelanin and Also, What Is Lurking Behind Those Dark Colors?

Vercruysse¹,

Govan²

2019

Preprint

View full text Add to dashboard Cite

We investigated the synthesis of melanin-like materials from DOPA, dopamine, norepinephrine and epinephrine in the presence of L-cysteine. We observed that L-cysteine delayed the formation of pigment from these catecholamines and that the presence of L-cysteine yielded darker-colored reaction mixtures. No reddish pigment was observed that would indicate the synthesis of pheomelanin-like material. The reactions were performed in the presence of Na2CO3 and through the addition of CaCl2 at the end of the reaction; the black, eumelanin-like material was co-precipitated with CaCO3. The remaining supernatant solutions were observed to be light-yellow to rusty-orange in color depending on the catecholamine used in the reaction. Size exclusion chromatography (SEC) analyses indicated that the removal of the black pigment left behind an oligomeric material that exhibited a strong absorbance band around 280nm. Our experimental and analytical observations prompt us to raise a number of points of discussion or hypotheses. 1) The presence of L-cysteine during the air-mediated oxidation of catecholamines leads to darker-colored pigments; not reddish or lighter-colored pigments that would visually resemble pheomelanin-like pigments, 2) SEC analyses suggested that the black pigment generated during the air-mediated oxidation of catecholamines is not necessarily the main reaction product, 3) The pre-formed, dark-colored pigments obtained through the air-mediated oxidative melanogenesis process can readily be deposited on insoluble mineral surfaces using an in situ co-precipitation procedure, 4) The air-mediated oxidation of catecholamines leads to a binary product that contains an insoluble, melanin-like substance and a soluble, oligo- or polymeric substance containing unoxidized precursor units, 5) The melanogenesis process leads to a binary product involving a non-covalently bonded combination of dark-colored pigment and a lighter-colored or colorless substance; the latter being understudied or ignored in the in vitro or in vivo studies of the melanogenesis process, 6) The kinetics of the melanogenesis process may determine the balance between insoluble and soluble components of the binary product generated; the slower the reaction the more dark-colored, insoluble pigment generated, 7) One should consider the possibility of intermolecularly, N-to-C, bonded units of catecholamines when evaluating the structure of melanins, polydopamines, etc. and 8) There is a need for a systematic study of the effect of amino acids (beyond just L-cysteine) and amines in general on the melanogenesis process.

show abstract

Synthesis and physiological implications of melanic pigments (Review)

Cited by 70 publications

References 49 publications

Outcomes of simultaneous vs. sequential pars plana vitrectomy and cataract surgery

Outcomes of simultaneous vs. sequential pars plana vitrectomy and cataract surgery

Intraocular pressure changes during and after silicone oil endotamponade (Review)

Melanogenesis: A Search for Pheomelanin and Also, What Is Lurking Behind Those Dark Colors?

Contact Info

Product

Resources

About